摘要
超声波探伤是大规格风电用齿轮钢的缺陷检测手段之一,而探伤缺陷的出现意味着使用性能的不合格。为了改善风电齿轮钢中超声探伤缺陷频出的问题,探究了这种缺陷的形成原因。通过缺陷观察和精炼过程取样分析,明确了缺陷的类型和形成阶段。再结合热力学计算得出缺陷夹杂物的形成原因,并提出工艺改进措施。结果表明,这些探伤缺陷是由固态的镁铝尖晶石与液态的CaO-MgO-Al_(2)O_(3)-SiO_(2)夹杂物聚集而成的大尺寸夹杂物,且外围附着少量CaS,尺寸为30~100μm。缺陷夹杂物的主体是CaO-MgO-Al_(2)O_(3)-SiO_(2)夹杂物,而该夹杂物源自VD过程产生的高SiO_(2)含量的CaO-MgO-Al_(2)O_(3)-SiO_(2)夹杂物。分析发现,VD过程钢液中过低的[Al]含量是高SiO_(2)含量的CaO-MgO-Al_(2)O_(3)-SiO_(2)夹杂物形成的根本原因。由于[Al]含量过低,钢液中的[Si]将夹杂物中的Al_(2)O_(3)还原,形成高SiO_(2)含量的CaO-MgO-Al_(2)O_(3)-SiO_(2)夹杂物;随着钢液中[Al]含量重新升高,夹杂物中的SiO_(2)被部分还原,但是仍然有高SiO_(2)含量的CaO-MgO-Al_(2)O_(3)-SiO_(2)夹杂物残留。提高VD过程钢液中的[Al]质量分数至0.010%以上是减少高SiO_(2)含量的CaO-MgO-Al_(2)O_(3)-SiO_(2)夹杂物出现的合理措施,从而可以达到有效降低风电齿轮钢中探伤缺陷出现率的目的。
Ultrasonic testing is one of the methods used for detecting defects in large-scale wind power gear steel, and the presence of defects indicates non-compliance with performance standards. To address the frequent occurrence of ultrasonic flaw detection in wind power gear steel, the causes of these defects was investigated. Through defect observation and refining process sampling analysis, the types of defects and their formation stages were identified. Then, the formation causes of defect inclusions was determined combined with thermodynamic calculations and process improvement measures was proposed. The results show that these ultrasonic flaw detections are large-sized inclusions formed by the aggregation of solid magnesium aluminum spinel and liquid CaO-MgO-Al_(2)O_(3)-SiO_(2) inclusions, with a small amount of CaS attached to the periphery. The size of these defect inclusions ranges from 30 μm to 100 μm. Analysis finds that low [Al] content in the VD process steel is the root cause of the formation of high SiO_(2) content CaO-MgO-Al_(2)O_(3)-SiO_(2) inclusions. Due to low [Al] content, [Si] in the steel liquid reduces the Al_(2)O_(3) in the inclusions, forming high SiO_(2) content CaO-MgO-Al_(2)O_(3)-SiO_(2) inclusions. As [Al] content in the steel liquid rised again, the SiO_(2) in the inclusions are partially reduced, but some high SiO_(2) content CaO-MgO-Al_(2)O_(3)-SiO_(2) inclusions are still remained. Increasing [Al] mass fraction in the steel liquid during the VD process to above 0.010% is a reasonable measure to reduce the occurrence of CaO-MgO-Al_(2)O_(3)-SiO_(2) inclusions with high SiO_(2) content, thereby effectively reducing the incidence of ultrasonic testing defects in wind power gear steel.
作者
俞杰
申文君
李占春
李义龙
张云天
成国光
YU Jie;SHEN Wenjun;LI Zhanchun;LI Yilong;ZHANG Yuntian;CHENG Guoguang(Special Steel Business Department,Jiangsu Yonggang Group Co.,Ltd.,Zhangjiagang 215628,Jiangsu,China;State Key Laboratory of Advanced Metallurgy,University of Science and Technology Beijing,Beijing 100083,China)
出处
《中国冶金》
CAS
CSCD
北大核心
2024年第9期122-131,共10页
China Metallurgy
